The technique as disclosed in a Non-Patent Reference is shown in FIG. 8, namely, in Item (6) of “thermal insulation of a roof” pp 192–193, extracted from a literature entitled “Explanation of Standard of Energy-Saving of Housing” published Jun. 1, 2002 by Foundation for Building Environment Energy Saving Organization, and it is a typical example of a thermal insulation of a roof of housing.
That is, rafters are fixed to a ridge pole, a purlin, a top plate and the like of a roof truss by nails, and a sub-roof member such as plywood and the like are fixed to the rafters by nails, then base bars for ventilation are fixed to the upper side surfaces of the rafters by nails as shown in FIG. 8(A), thereafter moisture-permeable waterproof sheet or a windbreak layer such as plywood and the like are fastened on the base bars for ventilation as shown in FIG. 8(B), thereby forming a ventilation layer between the sub-roof member and the windbreak layer.
Subsequently, as shown in FIG. 8(C), the heat insulators, which are cut to have a length corresponding to the interval between the rafters, are engaged between the rafters from an indoor side and fixed to the same by nails so as not to slide down, then the moisture-proof layer made of vinyl chloride or the like is fixed to the rafters by a tacker or the like from the lower side of the heat insulators.
FIG. 9 shows a heat shielding member as disclosed in Patent Reference which has been filed by the same applicant under No. 271,335, and laid open to public inspection Dec. 26, 2000 under No. 2000-355,989 and patented under U.S. Pat. No. 3,251,000.
That is, as shown in FIG. 9, the heat shielding member comprises an upper layer, an intermediate layer, a lower layer which have radiant heat reflective layers Re on upper faces thereof, and coupled with one another by a group of stand-up pieces which are freely laid down, wherein the respective spaces of an air layer are formed between respective layers for air ventilation. When the interior of an attic is subjected to thermal insulation, the heat shielding member is placed on a heat insulator disposed on a ceiling finishing member, as shown in FIG. 9(A), and the end edges of the upper layer of the heat shielding member are fixed to a structure member and the like, thereby keeping a stand-up state of the heat shielding member.
Further, when the roof is subjected to thermal insulation, as shown in FIG. 9(B), the heat shielding member is engaged between the rafters from the above and both sides of the upper layer are fixed to the upper surfaces of the rafters by a tacker or the like, then the heat insulator is brought into contact with the lower face of the heat shielding member and fixed to the same by nails and the like, thereafter a moisture-proof layer provided on the lower face of the heat insulator is fixed to the rafters by a tacker and the like, subsequently, a sub-roof member is disposed on the upper face of the heat shielding member and nailed and fixed to the rafters, and finally a waterproof layer and a roof finishing member are extended on the sub-roof member.
According to the first prior art shown in FIG. 8, although a ventilation layer, which is effective for discharging heat caused by high temperature heating from a roof surface, is formed, and an insulator having a desired thickness can be provided by selecting the height of the rafters, the heat insulator becomes an accumulation body having a large capacity owing to the heating from the roof, and hence even if the outside air temperature is lowered at night, the heat insulator continues to discharge heat, which deteriorates the indoor environment, requiring a long run of an air conditioner for cooling.
Further, according to the second prior art as shown in FIG. 9 which is an improvement of the thermal insulation structure of the first prior art, although the amount of heat accumulation in the heat insulator can be significantly restrained because the heat insulator is covered with the heat shielding member, the heat shielding member lacks in independence, and hence fixing and installation of the upper layer of the heat shielding member to the peripheral structure member are needed for holding the heat shielding member at a predetermined position. Accordingly, when the heat shielding member is applied to the thermal insulation of the roof as shown in FIG. 9(B), after the heat shielding member is fixed to the rafters, the sub-roof member needs to be extended on the heat shielding member 1, and when providing the heat shielding member, the installation from the indoor side is impossible and requires a complex, difficult and dangerous operation at high place from the top of the roof.
Still further, since the operation of providing the heat shielding member precedes the operation of extending the sub-roof member and the waterproof layer, this can not be effected in a rainy weather. If the heat shielding member gets wet during the provision thereof, causing a problem of mold growth and rot during the service life of a house.